The present invention pertains generally to counters or tallying devices which are actuated by vehicle passage over a sensing means in place on a roadway surface.
Widely used by various governmental departments are devices for tallying the number of vehicles moving along a traffic lane past a counting site. Toward this end collapsible road tubes are used in some installations along with pressure responsive transducer to provide a signal to a counter located at the side of the roadway.
Road tubes may be a length to extend across several lanes of traffic to provide the counter mechanism signals corresponding to cumulative traffic flow in all the lanes. A difficulty arises when it is desired to selectively count all traffic flow in a middle or inside lane of a multi-lane freeway or expressway. In such instances certain segments of the road tube would have to be shielded from being collapsed by the wheels of vehicles moving in the outside lane. Such shielding is, in the least, objectionable particularly since on such roadways vehicles move at high speed. Accordingly, a problem exists in the selective counting of vehicle passage in a middle or inner lane of a multi-lane roadway.